Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
dmv.community is one of the many independent Mastodon servers you can use to participate in the fediverse.
A small regional Mastodon instance for those in the DC, Maryland, and Virginia areas. Local news, commentary, and conversation.

Administered by:

Server stats:

155
active users

dmv.community: AboutStatusProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.3.7

#populationgenetics

0 posts0 participants0 posts today
Public *
Joanna Masel

Our new #preprint changes the way we look at an “extinction vortex” in which a small population loses fitness, causing it to become even smaller biorxiv.org/content/10.1101/20.
#MutationalMeltdown #EffectivePopulationSize #EvolutionaryRescue #PopulationGenetics #EvolGenPaper @wmawass @jdmatheson @uliseshmc 1/7

bioRxiv · Extinction vortices are driven more by a shortage of beneficial mutations than by deleterious mutation accumulationNatural populations are increasingly at risk of extinction due to climate change and habitat loss or fragmentation. The long-term viability of small populations can be threatened by an “extinction vortex” — a positive feedback loop between declining fitness and declining population size. Two distinct mechanisms can drive an extinction vortex: i) ineffective selection in small populations allows deleterious mutations to fix, driving “mutational meltdown”, and ii) fewer individuals produce fewer of the novel beneficial mutations essential for long-term adaptation, a mechanism we term “mutational drought”. We measure the relative importance of each mechanism, on the basis of how sensitive beneficial vs. deleterious components of fitness flux are to changes in census population size near the critical population size at which fitness is stable. We derive analytical results given linkage equilibrium, complemented by simulations that capture the complex linkage disequilibria that emerge under high deleterious mutation rates. Even in the absence of environmental change, mutational drought can be nearly as important as mutational meltdown. Real populations must also adapt to a changing environment, making mutational drought more important. A partial exception is that mutational drought is somewhat less important when the beneficial mutation rate is high, although its contribution remains substantial. Linkage between deleterious and beneficial mutations drives the critical population size substantially higher and increase (albeit modestly) the importance of mutational drought.
Public
Lukas VFN 🇪🇺

A #coral superhighway in the Indian Ocean phys.org/news/2024-03-coral-su

Integration of #PopulationGenetics with oceanographic models reveals strong connectivity among #CoralReefs across Seychelles nature.com/articles/s41598-024

"despite being scattered across more than a million square kilometers, remote coral #reefs across the #Seychelles are closely related... a network of #OceanCurrents scatter significant numbers of larvae between these distant islands"

underwater photo of a coral reef with lots of fish
Public
Joanna Masel

Our extensively revised preprint now goes beyond clarifying Haldane’s arguments about the #CostOfSelection / #SubstitutionalLoad / #SelectiveDeaths, it also significantly extends them, and applies the resulting model to data biorxiv.org/content/10.1101/20
@jdmatheson @moi #EvolgenPaper #PopulationGenetics #NaturalSelection #FitnessComponents #GeneticLoad 1/10

bioRxiv · The cost of selection in selective deaths paid out of reproductive excessHaldane’s Dilemma refers to the concern that the need for many “selective deaths” to complete a substitution (i.e. selective sweep) creates a speed limit to adaptation. However, discussion of this concern has been marked by confusion over which features of adaptation produce speed limits, what those limits are, and the consequences of violating speed limits. The term “substitution load” has been particularly unhelpful in this regard. Here we distinguish different historical lines of reasoning that lead to speed limits. We identify one line of reasoning, focused on finite reproductive excess, that has not yet been fully addressed. We develop this into a more general theoretical model that can apply to populations with any life history, even those for which a generation or even an individual are not well defined. We then apply this model to a dataset measuring survival of 517 different genotypes of Arabidopsis thaliana grown in eight different environmental conditions. These data suggest highly permissive limits to the speed of adaptation in all environmental conditions. This is because a much higher proportion of deaths contribute to adaptation than were anticipated during historical discussions of speed limits. ### Competing Interest Statement The authors have declared no competing interest.
Public
Carl T. Bergstrom

Intro post: I'm a professor of #Biology at the #UniversityOfWashington. My training is in #EvolutionaryBiology, #BehavioralEcology, #PopulationGenetics, and #Epidemiology. I did lots of work in #Bibliometrics and #NetworkTheory. I teach #DataLiteracy. These days I spend a lot of time thinking about the spread of #Misinformation, the #ScienceOfScience, and #PhilosophyOfScience. I do a lot of #BirdPhotography and love #ravens, #crows, and all #corvids.

For your trouble, here's a perfect crow.

Photograph of a wild crow on a black background.
ExploreLive feeds
About